
<!DOCTYPE HTML>
<html lang="zh-hans" >
    <head>
        <meta charset="UTF-8">
        <meta content="text/html; charset=utf-8" http-equiv="Content-Type">
        <title>方法值和方法表达式 · Go语言圣经</title>
        <meta http-equiv="X-UA-Compatible" content="IE=edge" />
        <meta name="description" content="">
        <meta name="generator" content="GitBook 3.2.3">
        
        
        
    
    <link rel="stylesheet" href="../gitbook/style.css">

    
            
                
                <link rel="stylesheet" href="../gitbook/gitbook-plugin-katex/katex.min.css">
                
            
                
                <link rel="stylesheet" href="../gitbook/gitbook-plugin-highlight/website.css">
                
            
                
                <link rel="stylesheet" href="../gitbook/gitbook-plugin-fontsettings/website.css">
                
            
        

    

    
        
    
        
    
        
    
        
    
        
    
        
    

        
    
    
    <meta name="HandheldFriendly" content="true"/>
    <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
    <meta name="apple-mobile-web-app-capable" content="yes">
    <meta name="apple-mobile-web-app-status-bar-style" content="black">
    <link rel="apple-touch-icon-precomposed" sizes="152x152" href="../gitbook/images/apple-touch-icon-precomposed-152.png">
    <link rel="shortcut icon" href="../gitbook/images/favicon.ico" type="image/x-icon">

    
    <link rel="next" href="ch6-05.html" />
    
    
    <link rel="prev" href="ch6-03.html" />
    

    </head>
    <body>
        
<div class="book">
    <div class="book-summary">
        
            
            
                <nav role="navigation">
                


<ul class="summary">
    
    

    

    
        
        
    
        <li class="chapter " data-level="1.1" data-path="../">
            
                <a href="../">
            
                    
                    前言
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.1.1" data-path="../ch0/ch0-01.html">
            
                <a href="../ch0/ch0-01.html">
            
                    
                    Go语言起源
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.1.2" data-path="../ch0/ch0-02.html">
            
                <a href="../ch0/ch0-02.html">
            
                    
                    Go语言项目
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.1.3" data-path="../ch0/ch0-03.html">
            
                <a href="../ch0/ch0-03.html">
            
                    
                    本书的组织
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.1.4" data-path="../ch0/ch0-04.html">
            
                <a href="../ch0/ch0-04.html">
            
                    
                    更多的信息
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.1.5" data-path="../ch0/ch0-05.html">
            
                <a href="../ch0/ch0-05.html">
            
                    
                    致谢
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.2" data-path="../ch1/ch1.html">
            
                <a href="../ch1/ch1.html">
            
                    
                    入门
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.2.1" data-path="../ch1/ch1-01.html">
            
                <a href="../ch1/ch1-01.html">
            
                    
                    Hello, World
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.2.2" data-path="../ch1/ch1-02.html">
            
                <a href="../ch1/ch1-02.html">
            
                    
                    命令行参数
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.2.3" data-path="../ch1/ch1-03.html">
            
                <a href="../ch1/ch1-03.html">
            
                    
                    查找重复的行
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.2.4" data-path="../ch1/ch1-04.html">
            
                <a href="../ch1/ch1-04.html">
            
                    
                    GIF动画
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.2.5" data-path="../ch1/ch1-05.html">
            
                <a href="../ch1/ch1-05.html">
            
                    
                    获取URL
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.2.6" data-path="../ch1/ch1-06.html">
            
                <a href="../ch1/ch1-06.html">
            
                    
                    并发获取多个URL
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.2.7" data-path="../ch1/ch1-07.html">
            
                <a href="../ch1/ch1-07.html">
            
                    
                    Web服务
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.2.8" data-path="../ch1/ch1-08.html">
            
                <a href="../ch1/ch1-08.html">
            
                    
                    本章要点
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.3" data-path="../ch2/ch2.html">
            
                <a href="../ch2/ch2.html">
            
                    
                    程序结构
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.3.1" data-path="../ch2/ch2-01.html">
            
                <a href="../ch2/ch2-01.html">
            
                    
                    命名
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.2" data-path="../ch2/ch2-02.html">
            
                <a href="../ch2/ch2-02.html">
            
                    
                    声明
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.3" data-path="../ch2/ch2-03.html">
            
                <a href="../ch2/ch2-03.html">
            
                    
                    变量
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.4" data-path="../ch2/ch2-04.html">
            
                <a href="../ch2/ch2-04.html">
            
                    
                    赋值
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.5" data-path="../ch2/ch2-05.html">
            
                <a href="../ch2/ch2-05.html">
            
                    
                    类型
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.6" data-path="../ch2/ch2-06.html">
            
                <a href="../ch2/ch2-06.html">
            
                    
                    包和文件
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.7" data-path="../ch2/ch2-07.html">
            
                <a href="../ch2/ch2-07.html">
            
                    
                    作用域
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.4" data-path="../ch3/ch3.html">
            
                <a href="../ch3/ch3.html">
            
                    
                    基础数据类型
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.4.1" data-path="../ch3/ch3-01.html">
            
                <a href="../ch3/ch3-01.html">
            
                    
                    整型
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.2" data-path="../ch3/ch3-02.html">
            
                <a href="../ch3/ch3-02.html">
            
                    
                    浮点数
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.3" data-path="../ch3/ch3-03.html">
            
                <a href="../ch3/ch3-03.html">
            
                    
                    复数
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.4" data-path="../ch3/ch3-04.html">
            
                <a href="../ch3/ch3-04.html">
            
                    
                    布尔型
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.5" data-path="../ch3/ch3-05.html">
            
                <a href="../ch3/ch3-05.html">
            
                    
                    字符串
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.6" data-path="../ch3/ch3-06.html">
            
                <a href="../ch3/ch3-06.html">
            
                    
                    常量
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.5" data-path="../ch4/ch4.html">
            
                <a href="../ch4/ch4.html">
            
                    
                    复合数据类型
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.5.1" data-path="../ch4/ch4-01.html">
            
                <a href="../ch4/ch4-01.html">
            
                    
                    数组
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.5.2" data-path="../ch4/ch4-02.html">
            
                <a href="../ch4/ch4-02.html">
            
                    
                    Slice
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.5.3" data-path="../ch4/ch4-03.html">
            
                <a href="../ch4/ch4-03.html">
            
                    
                    Map
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.5.4" data-path="../ch4/ch4-04.html">
            
                <a href="../ch4/ch4-04.html">
            
                    
                    结构体
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.5.5" data-path="../ch4/ch4-05.html">
            
                <a href="../ch4/ch4-05.html">
            
                    
                    JSON
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.5.6" data-path="../ch4/ch4-06.html">
            
                <a href="../ch4/ch4-06.html">
            
                    
                    文本和HTML模板
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.6" data-path="../ch5/ch5.html">
            
                <a href="../ch5/ch5.html">
            
                    
                    函数
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.6.1" data-path="../ch5/ch5-01.html">
            
                <a href="../ch5/ch5-01.html">
            
                    
                    函数声明
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.2" data-path="../ch5/ch5-02.html">
            
                <a href="../ch5/ch5-02.html">
            
                    
                    递归
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.3" data-path="../ch5/ch5-03.html">
            
                <a href="../ch5/ch5-03.html">
            
                    
                    多返回值
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.4" data-path="../ch5/ch5-04.html">
            
                <a href="../ch5/ch5-04.html">
            
                    
                    错误
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.5" data-path="../ch5/ch5-05.html">
            
                <a href="../ch5/ch5-05.html">
            
                    
                    函数值
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.6" data-path="../ch5/ch5-06.html">
            
                <a href="../ch5/ch5-06.html">
            
                    
                    匿名函数
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.7" data-path="../ch5/ch5-07.html">
            
                <a href="../ch5/ch5-07.html">
            
                    
                    可变参数
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.8" data-path="../ch5/ch5-08.html">
            
                <a href="../ch5/ch5-08.html">
            
                    
                    Deferred函数
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.9" data-path="../ch5/ch5-09.html">
            
                <a href="../ch5/ch5-09.html">
            
                    
                    Panic异常
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.10" data-path="../ch5/ch5-10.html">
            
                <a href="../ch5/ch5-10.html">
            
                    
                    Recover捕获异常
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.7" data-path="ch6.html">
            
                <a href="ch6.html">
            
                    
                    方法
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.7.1" data-path="ch6-01.html">
            
                <a href="ch6-01.html">
            
                    
                    方法声明
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.7.2" data-path="ch6-02.html">
            
                <a href="ch6-02.html">
            
                    
                    基于指针对象的方法
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.7.3" data-path="ch6-03.html">
            
                <a href="ch6-03.html">
            
                    
                    通过嵌入结构体来扩展类型
            
                </a>
            

            
        </li>
    
        <li class="chapter active" data-level="1.7.4" data-path="ch6-04.html">
            
                <a href="ch6-04.html">
            
                    
                    方法值和方法表达式
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.7.5" data-path="ch6-05.html">
            
                <a href="ch6-05.html">
            
                    
                    示例: Bit数组
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.7.6" data-path="ch6-06.html">
            
                <a href="ch6-06.html">
            
                    
                    封装
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.8" data-path="../ch7/ch7.html">
            
                <a href="../ch7/ch7.html">
            
                    
                    接口
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.8.1" data-path="../ch7/ch7-01.html">
            
                <a href="../ch7/ch7-01.html">
            
                    
                    接口是合约
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.2" data-path="../ch7/ch7-02.html">
            
                <a href="../ch7/ch7-02.html">
            
                    
                    接口类型
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.3" data-path="../ch7/ch7-03.html">
            
                <a href="../ch7/ch7-03.html">
            
                    
                    实现接口的条件
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.4" data-path="../ch7/ch7-04.html">
            
                <a href="../ch7/ch7-04.html">
            
                    
                    flag.Value接口
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.5" data-path="../ch7/ch7-05.html">
            
                <a href="../ch7/ch7-05.html">
            
                    
                    接口值
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.6" data-path="../ch7/ch7-06.html">
            
                <a href="../ch7/ch7-06.html">
            
                    
                    sort.Interface接口
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.7" data-path="../ch7/ch7-07.html">
            
                <a href="../ch7/ch7-07.html">
            
                    
                    http.Handler接口
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.8" data-path="../ch7/ch7-08.html">
            
                <a href="../ch7/ch7-08.html">
            
                    
                    error接口
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.9" data-path="../ch7/ch7-09.html">
            
                <a href="../ch7/ch7-09.html">
            
                    
                    示例: 表达式求值
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.10" data-path="../ch7/ch7-10.html">
            
                <a href="../ch7/ch7-10.html">
            
                    
                    类型断言
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.11" data-path="../ch7/ch7-11.html">
            
                <a href="../ch7/ch7-11.html">
            
                    
                    基于类型断言识别错误类型
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.12" data-path="../ch7/ch7-12.html">
            
                <a href="../ch7/ch7-12.html">
            
                    
                    通过类型断言查询接口
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.13" data-path="../ch7/ch7-13.html">
            
                <a href="../ch7/ch7-13.html">
            
                    
                    类型分支
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.14" data-path="../ch7/ch7-14.html">
            
                <a href="../ch7/ch7-14.html">
            
                    
                    示例: 基于标记的XML解码
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.15" data-path="../ch7/ch7-15.html">
            
                <a href="../ch7/ch7-15.html">
            
                    
                    补充几点
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.9" data-path="../ch8/ch8.html">
            
                <a href="../ch8/ch8.html">
            
                    
                    Goroutines和Channels
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.9.1" data-path="../ch8/ch8-01.html">
            
                <a href="../ch8/ch8-01.html">
            
                    
                    Goroutines
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.9.2" data-path="../ch8/ch8-02.html">
            
                <a href="../ch8/ch8-02.html">
            
                    
                    示例: 并发的Clock服务
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.9.3" data-path="../ch8/ch8-03.html">
            
                <a href="../ch8/ch8-03.html">
            
                    
                    示例: 并发的Echo服务
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.9.4" data-path="../ch8/ch8-04.html">
            
                <a href="../ch8/ch8-04.html">
            
                    
                    Channels
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.9.5" data-path="../ch8/ch8-05.html">
            
                <a href="../ch8/ch8-05.html">
            
                    
                    并发的循环
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.9.6" data-path="../ch8/ch8-06.html">
            
                <a href="../ch8/ch8-06.html">
            
                    
                    示例: 并发的Web爬虫
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.9.7" data-path="../ch8/ch8-07.html">
            
                <a href="../ch8/ch8-07.html">
            
                    
                    基于select的多路复用
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.9.8" data-path="../ch8/ch8-08.html">
            
                <a href="../ch8/ch8-08.html">
            
                    
                    示例: 并发的目录遍历
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.9.9" data-path="../ch8/ch8-09.html">
            
                <a href="../ch8/ch8-09.html">
            
                    
                    并发的退出
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.9.10" data-path="../ch8/ch8-10.html">
            
                <a href="../ch8/ch8-10.html">
            
                    
                    示例: 聊天服务
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.10" data-path="../ch9/ch9.html">
            
                <a href="../ch9/ch9.html">
            
                    
                    基于共享变量的并发
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.10.1" data-path="../ch9/ch9-01.html">
            
                <a href="../ch9/ch9-01.html">
            
                    
                    竞争条件
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.10.2" data-path="../ch9/ch9-02.html">
            
                <a href="../ch9/ch9-02.html">
            
                    
                    sync.Mutex互斥锁
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.10.3" data-path="../ch9/ch9-03.html">
            
                <a href="../ch9/ch9-03.html">
            
                    
                    sync.RWMutex读写锁
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.10.4" data-path="../ch9/ch9-04.html">
            
                <a href="../ch9/ch9-04.html">
            
                    
                    内存同步
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.10.5" data-path="../ch9/ch9-05.html">
            
                <a href="../ch9/ch9-05.html">
            
                    
                    sync.Once惰性初始化
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.10.6" data-path="../ch9/ch9-06.html">
            
                <a href="../ch9/ch9-06.html">
            
                    
                    竞争条件检测
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.10.7" data-path="../ch9/ch9-07.html">
            
                <a href="../ch9/ch9-07.html">
            
                    
                    示例: 并发的非阻塞缓存
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.10.8" data-path="../ch9/ch9-08.html">
            
                <a href="../ch9/ch9-08.html">
            
                    
                    Goroutines和线程
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.11" data-path="../ch10/ch10.html">
            
                <a href="../ch10/ch10.html">
            
                    
                    包和工具
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.11.1" data-path="../ch10/ch10-01.html">
            
                <a href="../ch10/ch10-01.html">
            
                    
                    包简介
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.11.2" data-path="../ch10/ch10-02.html">
            
                <a href="../ch10/ch10-02.html">
            
                    
                    导入路径
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.11.3" data-path="../ch10/ch10-03.html">
            
                <a href="../ch10/ch10-03.html">
            
                    
                    包声明
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.11.4" data-path="../ch10/ch10-04.html">
            
                <a href="../ch10/ch10-04.html">
            
                    
                    导入声明
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.11.5" data-path="../ch10/ch10-05.html">
            
                <a href="../ch10/ch10-05.html">
            
                    
                    包的匿名导入
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.11.6" data-path="../ch10/ch10-06.html">
            
                <a href="../ch10/ch10-06.html">
            
                    
                    包和命名
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.11.7" data-path="../ch10/ch10-07.html">
            
                <a href="../ch10/ch10-07.html">
            
                    
                    工具
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.12" data-path="../ch11/ch11.html">
            
                <a href="../ch11/ch11.html">
            
                    
                    测试
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.12.1" data-path="../ch11/ch11-01.html">
            
                <a href="../ch11/ch11-01.html">
            
                    
                    go test
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.12.2" data-path="../ch11/ch11-02.html">
            
                <a href="../ch11/ch11-02.html">
            
                    
                    测试函数
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.12.3" data-path="../ch11/ch11-03.html">
            
                <a href="../ch11/ch11-03.html">
            
                    
                    测试覆盖率
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.12.4" data-path="../ch11/ch11-04.html">
            
                <a href="../ch11/ch11-04.html">
            
                    
                    基准测试
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.12.5" data-path="../ch11/ch11-05.html">
            
                <a href="../ch11/ch11-05.html">
            
                    
                    剖析
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.12.6" data-path="../ch11/ch11-06.html">
            
                <a href="../ch11/ch11-06.html">
            
                    
                    示例函数
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.13" data-path="../ch12/ch12.html">
            
                <a href="../ch12/ch12.html">
            
                    
                    反射
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.13.1" data-path="../ch12/ch12-01.html">
            
                <a href="../ch12/ch12-01.html">
            
                    
                    为何需要反射?
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.13.2" data-path="../ch12/ch12-02.html">
            
                <a href="../ch12/ch12-02.html">
            
                    
                    reflect.Type和reflect.Value
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.13.3" data-path="../ch12/ch12-03.html">
            
                <a href="../ch12/ch12-03.html">
            
                    
                    Display递归打印
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.13.4" data-path="../ch12/ch12-04.html">
            
                <a href="../ch12/ch12-04.html">
            
                    
                    示例: 编码S表达式
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.13.5" data-path="../ch12/ch12-05.html">
            
                <a href="../ch12/ch12-05.html">
            
                    
                    通过reflect.Value修改值
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.13.6" data-path="../ch12/ch12-06.html">
            
                <a href="../ch12/ch12-06.html">
            
                    
                    示例: 解码S表达式
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.13.7" data-path="../ch12/ch12-07.html">
            
                <a href="../ch12/ch12-07.html">
            
                    
                    获取结构体字段标签
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.13.8" data-path="../ch12/ch12-08.html">
            
                <a href="../ch12/ch12-08.html">
            
                    
                    显示一个类型的方法集
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.13.9" data-path="../ch12/ch12-09.html">
            
                <a href="../ch12/ch12-09.html">
            
                    
                    几点忠告
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.14" data-path="../ch13/ch13.html">
            
                <a href="../ch13/ch13.html">
            
                    
                    底层编程
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.14.1" data-path="../ch13/ch13-01.html">
            
                <a href="../ch13/ch13-01.html">
            
                    
                    unsafe.Sizeof, Alignof 和 Offsetof
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.14.2" data-path="../ch13/ch13-02.html">
            
                <a href="../ch13/ch13-02.html">
            
                    
                    unsafe.Pointer
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.14.3" data-path="../ch13/ch13-03.html">
            
                <a href="../ch13/ch13-03.html">
            
                    
                    示例: 深度相等判断
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.14.4" data-path="../ch13/ch13-04.html">
            
                <a href="../ch13/ch13-04.html">
            
                    
                    通过cgo调用C代码
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.14.5" data-path="../ch13/ch13-05.html">
            
                <a href="../ch13/ch13-05.html">
            
                    
                    几点忠告
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.15" data-path="../appendix/appendix.html">
            
                <a href="../appendix/appendix.html">
            
                    
                    附录
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.15.1" data-path="../appendix/appendix-a-errata.html">
            
                <a href="../appendix/appendix-a-errata.html">
            
                    
                    附录A：原文勘误
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.15.2" data-path="../appendix/appendix-b-author.html">
            
                <a href="../appendix/appendix-b-author.html">
            
                    
                    附录B：作者译者
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.15.3" data-path="../appendix/appendix-c-cpoyright.html">
            
                <a href="../appendix/appendix-c-cpoyright.html">
            
                    
                    附录C：译文授权
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.15.4" data-path="../appendix/appendix-d-translations.html">
            
                <a href="../appendix/appendix-d-translations.html">
            
                    
                    附录D：其它语言
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    

    

    <li class="divider"></li>

    <li>
        <a href="https://www.gitbook.com" target="blank" class="gitbook-link">
            本书使用 GitBook 发布
        </a>
    </li>
</ul>


                </nav>
            
        
    </div>

    <div class="book-body">
        
            <div class="body-inner">
                
                    

<div class="book-header" role="navigation">
    

    <!-- Title -->
    <h1>
        <i class="fa fa-circle-o-notch fa-spin"></i>
        <a href=".." >方法值和方法表达式</a>
    </h1>
</div>




                    <div class="page-wrapper" tabindex="-1" role="main">
                        <div class="page-inner">
                            
                                <section class="normal markdown-section">
                                
                                <h2 id="64-&#x65B9;&#x6CD5;&#x503C;&#x548C;&#x65B9;&#x6CD5;&#x8868;&#x8FBE;&#x5F0F;">6.4. &#x65B9;&#x6CD5;&#x503C;&#x548C;&#x65B9;&#x6CD5;&#x8868;&#x8FBE;&#x5F0F;</h2>
<p>&#x6211;&#x4EEC;&#x7ECF;&#x5E38;&#x9009;&#x62E9;&#x4E00;&#x4E2A;&#x65B9;&#x6CD5;&#xFF0C;&#x5E76;&#x4E14;&#x5728;&#x540C;&#x4E00;&#x4E2A;&#x8868;&#x8FBE;&#x5F0F;&#x91CC;&#x6267;&#x884C;&#xFF0C;&#x6BD4;&#x5982;&#x5E38;&#x89C1;&#x7684;p.Distance()&#x5F62;&#x5F0F;&#xFF0C;&#x5B9E;&#x9645;&#x4E0A;&#x5C06;&#x5176;&#x5206;&#x6210;&#x4E24;&#x6B65;&#x6765;&#x6267;&#x884C;&#x4E5F;&#x662F;&#x53EF;&#x80FD;&#x7684;&#x3002;p.Distance&#x53EB;&#x4F5C;&#x201C;&#x9009;&#x62E9;&#x5668;&#x201D;&#xFF0C;&#x9009;&#x62E9;&#x5668;&#x4F1A;&#x8FD4;&#x56DE;&#x4E00;&#x4E2A;&#x65B9;&#x6CD5;&#x201C;&#x503C;&#x201D;-&gt;&#x4E00;&#x4E2A;&#x5C06;&#x65B9;&#x6CD5;&#xFF08;Point.Distance&#xFF09;&#x7ED1;&#x5B9A;&#x5230;&#x7279;&#x5B9A;&#x63A5;&#x6536;&#x5668;&#x53D8;&#x91CF;&#x7684;&#x51FD;&#x6570;&#x3002;&#x8FD9;&#x4E2A;&#x51FD;&#x6570;&#x53EF;&#x4EE5;&#x4E0D;&#x901A;&#x8FC7;&#x6307;&#x5B9A;&#x5176;&#x63A5;&#x6536;&#x5668;&#x5373;&#x53EF;&#x88AB;&#x8C03;&#x7528;&#xFF1B;&#x5373;&#x8C03;&#x7528;&#x65F6;&#x4E0D;&#x9700;&#x8981;&#x6307;&#x5B9A;&#x63A5;&#x6536;&#x5668;&#xFF08;&#x8BD1;&#x6CE8;&#xFF1A;&#x56E0;&#x4E3A;&#x5DF2;&#x7ECF;&#x5728;&#x524D;&#x6587;&#x4E2D;&#x6307;&#x5B9A;&#x8FC7;&#x4E86;&#xFF09;&#xFF0C;&#x53EA;&#x8981;&#x4F20;&#x5165;&#x51FD;&#x6570;&#x7684;&#x53C2;&#x6570;&#x5373;&#x53EF;&#xFF1A;</p>
<pre><code class="lang-go">p := Point{<span class="hljs-number">1</span>, <span class="hljs-number">2</span>}
q := Point{<span class="hljs-number">4</span>, <span class="hljs-number">6</span>}

distanceFromP := p.Distance        <span class="hljs-comment">// method value</span>
fmt.Println(distanceFromP(q))      <span class="hljs-comment">// &quot;5&quot;</span>
<span class="hljs-keyword">var</span> origin Point                   <span class="hljs-comment">// {0, 0}</span>
fmt.Println(distanceFromP(origin)) <span class="hljs-comment">// &quot;2.23606797749979&quot;, sqrt(5)</span>

scaleP := p.ScaleBy <span class="hljs-comment">// method value</span>
scaleP(<span class="hljs-number">2</span>)           <span class="hljs-comment">// p becomes (2, 4)</span>
scaleP(<span class="hljs-number">3</span>)           <span class="hljs-comment">//      then (6, 12)</span>
scaleP(<span class="hljs-number">10</span>)          <span class="hljs-comment">//      then (60, 120)</span>
</code></pre>
<p>&#x5728;&#x4E00;&#x4E2A;&#x5305;&#x7684;API&#x9700;&#x8981;&#x4E00;&#x4E2A;&#x51FD;&#x6570;&#x503C;&#x3001;&#x4E14;&#x8C03;&#x7528;&#x65B9;&#x5E0C;&#x671B;&#x64CD;&#x4F5C;&#x7684;&#x662F;&#x67D0;&#x4E00;&#x4E2A;&#x7ED1;&#x5B9A;&#x4E86;&#x5BF9;&#x8C61;&#x7684;&#x65B9;&#x6CD5;&#x7684;&#x8BDD;&#xFF0C;&#x65B9;&#x6CD5;&#x201C;&#x503C;&#x201D;&#x4F1A;&#x975E;&#x5E38;&#x5B9E;&#x7528;&#xFF08;<code>`=_=</code>&#x771F;&#x662F;&#x7ED5;&#xFF09;&#x3002;&#x4E3E;&#x4F8B;&#x6765;&#x8BF4;&#xFF0C;&#x4E0B;&#x9762;&#x4F8B;&#x5B50;&#x4E2D;&#x7684;time.AfterFunc&#x8FD9;&#x4E2A;&#x51FD;&#x6570;&#x7684;&#x529F;&#x80FD;&#x662F;&#x5728;&#x6307;&#x5B9A;&#x7684;&#x5EF6;&#x8FDF;&#x65F6;&#x95F4;&#x4E4B;&#x540E;&#x6765;&#x6267;&#x884C;&#x4E00;&#x4E2A;&#xFF08;&#x8BD1;&#x6CE8;&#xFF1A;&#x53E6;&#x5916;&#x7684;&#xFF09;&#x51FD;&#x6570;&#x3002;&#x4E14;&#x8FD9;&#x4E2A;&#x51FD;&#x6570;&#x64CD;&#x4F5C;&#x7684;&#x662F;&#x4E00;&#x4E2A;Rocket&#x5BF9;&#x8C61;r</p>
<pre><code class="lang-go"><span class="hljs-keyword">type</span> Rocket <span class="hljs-keyword">struct</span> { <span class="hljs-comment">/* ... */</span> }
<span class="hljs-keyword">func</span> (r *Rocket) Launch() { <span class="hljs-comment">/* ... */</span> }
r := <span class="hljs-built_in">new</span>(Rocket)
time.AfterFunc(<span class="hljs-number">10</span> * time.Second, <span class="hljs-keyword">func</span>() { r.Launch() })
</code></pre>
<p>&#x76F4;&#x63A5;&#x7528;&#x65B9;&#x6CD5;&#x201C;&#x503C;&#x201D;&#x4F20;&#x5165;AfterFunc&#x7684;&#x8BDD;&#x53EF;&#x4EE5;&#x66F4;&#x4E3A;&#x7B80;&#x77ED;&#xFF1A;</p>
<pre><code class="lang-go">time.AfterFunc(<span class="hljs-number">10</span> * time.Second, r.Launch)
</code></pre>
<p>&#x8BD1;&#x6CE8;&#xFF1A;&#x7701;&#x6389;&#x4E86;&#x4E0A;&#x9762;&#x90A3;&#x4E2A;&#x4F8B;&#x5B50;&#x91CC;&#x7684;&#x533F;&#x540D;&#x51FD;&#x6570;&#x3002;</p>
<p>&#x548C;&#x65B9;&#x6CD5;&#x201C;&#x503C;&#x201D;&#x76F8;&#x5173;&#x7684;&#x8FD8;&#x6709;&#x65B9;&#x6CD5;&#x8868;&#x8FBE;&#x5F0F;&#x3002;&#x5F53;&#x8C03;&#x7528;&#x4E00;&#x4E2A;&#x65B9;&#x6CD5;&#x65F6;&#xFF0C;&#x4E0E;&#x8C03;&#x7528;&#x4E00;&#x4E2A;&#x666E;&#x901A;&#x7684;&#x51FD;&#x6570;&#x76F8;&#x6BD4;&#xFF0C;&#x6211;&#x4EEC;&#x5FC5;&#x987B;&#x8981;&#x7528;&#x9009;&#x62E9;&#x5668;&#xFF08;p.Distance&#xFF09;&#x8BED;&#x6CD5;&#x6765;&#x6307;&#x5B9A;&#x65B9;&#x6CD5;&#x7684;&#x63A5;&#x6536;&#x5668;&#x3002;</p>
<p>&#x5F53;T&#x662F;&#x4E00;&#x4E2A;&#x7C7B;&#x578B;&#x65F6;&#xFF0C;&#x65B9;&#x6CD5;&#x8868;&#x8FBE;&#x5F0F;&#x53EF;&#x80FD;&#x4F1A;&#x5199;&#x4F5C;<code>T.f</code>&#x6216;&#x8005;<code>(*T).f</code>&#xFF0C;&#x4F1A;&#x8FD4;&#x56DE;&#x4E00;&#x4E2A;&#x51FD;&#x6570;&#x201C;&#x503C;&#x201D;&#xFF0C;&#x8FD9;&#x79CD;&#x51FD;&#x6570;&#x4F1A;&#x5C06;&#x5176;&#x7B2C;&#x4E00;&#x4E2A;&#x53C2;&#x6570;&#x7528;&#x4F5C;&#x63A5;&#x6536;&#x5668;&#xFF0C;&#x6240;&#x4EE5;&#x53EF;&#x4EE5;&#x7528;&#x901A;&#x5E38;&#xFF08;&#x8BD1;&#x6CE8;&#xFF1A;&#x4E0D;&#x5199;&#x9009;&#x62E9;&#x5668;&#xFF09;&#x7684;&#x65B9;&#x5F0F;&#x6765;&#x5BF9;&#x5176;&#x8FDB;&#x884C;&#x8C03;&#x7528;&#xFF1A;</p>
<pre><code class="lang-go">p := Point{<span class="hljs-number">1</span>, <span class="hljs-number">2</span>}
q := Point{<span class="hljs-number">4</span>, <span class="hljs-number">6</span>}

distance := Point.Distance   <span class="hljs-comment">// method expression</span>
fmt.Println(distance(p, q))  <span class="hljs-comment">// &quot;5&quot;</span>
fmt.Printf(<span class="hljs-string">&quot;%T\n&quot;</span>, distance) <span class="hljs-comment">// &quot;func(Point, Point) float64&quot;</span>

scale := (*Point).ScaleBy
scale(&amp;p, <span class="hljs-number">2</span>)
fmt.Println(p)            <span class="hljs-comment">// &quot;{2 4}&quot;</span>
fmt.Printf(<span class="hljs-string">&quot;%T\n&quot;</span>, scale) <span class="hljs-comment">// &quot;func(*Point, float64)&quot;</span>

<span class="hljs-comment">// &#x8BD1;&#x6CE8;&#xFF1A;&#x8FD9;&#x4E2A;Distance&#x5B9E;&#x9645;&#x4E0A;&#x662F;&#x6307;&#x5B9A;&#x4E86;Point&#x5BF9;&#x8C61;&#x4E3A;&#x63A5;&#x6536;&#x5668;&#x7684;&#x4E00;&#x4E2A;&#x65B9;&#x6CD5;func (p Point) Distance()&#xFF0C;</span>
<span class="hljs-comment">// &#x4F46;&#x901A;&#x8FC7;Point.Distance&#x5F97;&#x5230;&#x7684;&#x51FD;&#x6570;&#x9700;&#x8981;&#x6BD4;&#x5B9E;&#x9645;&#x7684;Distance&#x65B9;&#x6CD5;&#x591A;&#x4E00;&#x4E2A;&#x53C2;&#x6570;&#xFF0C;</span>
<span class="hljs-comment">// &#x5373;&#x5176;&#x9700;&#x8981;&#x7528;&#x7B2C;&#x4E00;&#x4E2A;&#x989D;&#x5916;&#x53C2;&#x6570;&#x6307;&#x5B9A;&#x63A5;&#x6536;&#x5668;&#xFF0C;&#x540E;&#x9762;&#x6392;&#x5217;Distance&#x65B9;&#x6CD5;&#x7684;&#x53C2;&#x6570;&#x3002;</span>
<span class="hljs-comment">// &#x770B;&#x8D77;&#x6765;&#x672C;&#x4E66;&#x4E2D;&#x51FD;&#x6570;&#x548C;&#x65B9;&#x6CD5;&#x7684;&#x533A;&#x522B;&#x662F;&#x6307;&#x6709;&#x6CA1;&#x6709;&#x63A5;&#x6536;&#x5668;&#xFF0C;&#x800C;&#x4E0D;&#x50CF;&#x5176;&#x4ED6;&#x8BED;&#x8A00;&#x90A3;&#x6837;&#x662F;&#x6307;&#x6709;&#x6CA1;&#x6709;&#x8FD4;&#x56DE;&#x503C;&#x3002;</span>
</code></pre>
<p>&#x5F53;&#x4F60;&#x6839;&#x636E;&#x4E00;&#x4E2A;&#x53D8;&#x91CF;&#x6765;&#x51B3;&#x5B9A;&#x8C03;&#x7528;&#x540C;&#x4E00;&#x4E2A;&#x7C7B;&#x578B;&#x7684;&#x54EA;&#x4E2A;&#x51FD;&#x6570;&#x65F6;&#xFF0C;&#x65B9;&#x6CD5;&#x8868;&#x8FBE;&#x5F0F;&#x5C31;&#x663E;&#x5F97;&#x5F88;&#x6709;&#x7528;&#x4E86;&#x3002;&#x4F60;&#x53EF;&#x4EE5;&#x6839;&#x636E;&#x9009;&#x62E9;&#x6765;&#x8C03;&#x7528;&#x63A5;&#x6536;&#x5668;&#x5404;&#x4E0D;&#x76F8;&#x540C;&#x7684;&#x65B9;&#x6CD5;&#x3002;&#x4E0B;&#x9762;&#x7684;&#x4F8B;&#x5B50;&#xFF0C;&#x53D8;&#x91CF;op&#x4EE3;&#x8868;Point&#x7C7B;&#x578B;&#x7684;addition&#x6216;&#x8005;subtraction&#x65B9;&#x6CD5;&#xFF0C;Path.TranslateBy&#x65B9;&#x6CD5;&#x4F1A;&#x4E3A;&#x5176;Path&#x6570;&#x7EC4;&#x4E2D;&#x7684;&#x6BCF;&#x4E00;&#x4E2A;Point&#x6765;&#x8C03;&#x7528;&#x5BF9;&#x5E94;&#x7684;&#x65B9;&#x6CD5;&#xFF1A;</p>
<pre><code class="lang-go"><span class="hljs-keyword">type</span> Point <span class="hljs-keyword">struct</span>{ X, Y <span class="hljs-keyword">float64</span> }

<span class="hljs-keyword">func</span> (p Point) Add(q Point) Point { <span class="hljs-keyword">return</span> Point{p.X + q.X, p.Y + q.Y} }
<span class="hljs-keyword">func</span> (p Point) Sub(q Point) Point { <span class="hljs-keyword">return</span> Point{p.X - q.X, p.Y - q.Y} }

<span class="hljs-keyword">type</span> Path []Point

<span class="hljs-keyword">func</span> (path Path) TranslateBy(offset Point, add <span class="hljs-keyword">bool</span>) {
    <span class="hljs-keyword">var</span> op <span class="hljs-keyword">func</span>(p, q Point) Point
    <span class="hljs-keyword">if</span> add {
        op = Point.Add
    } <span class="hljs-keyword">else</span> {
        op = Point.Sub
    }
    <span class="hljs-keyword">for</span> i := <span class="hljs-keyword">range</span> path {
        <span class="hljs-comment">// Call either path[i].Add(offset) or path[i].Sub(offset).</span>
        path[i] = op(path[i], offset)
    }
}
</code></pre>

                                
                                </section>
                            
                        </div>
                    </div>
                
            </div>

            
                
                <a href="ch6-03.html" class="navigation navigation-prev " aria-label="Previous page: 通过嵌入结构体来扩展类型">
                    <i class="fa fa-angle-left"></i>
                </a>
                
                
                <a href="ch6-05.html" class="navigation navigation-next " aria-label="Next page: 示例: Bit数组">
                    <i class="fa fa-angle-right"></i>
                </a>
                
            
        
    </div>

    <script>
        var gitbook = gitbook || [];
        gitbook.push(function() {
            gitbook.page.hasChanged({"page":{"title":"方法值和方法表达式","level":"1.7.4","depth":2,"next":{"title":"示例: Bit数组","level":"1.7.5","depth":2,"path":"ch6/ch6-05.md","ref":"ch6/ch6-05.md","articles":[]},"previous":{"title":"通过嵌入结构体来扩展类型","level":"1.7.3","depth":2,"path":"ch6/ch6-03.md","ref":"ch6/ch6-03.md","articles":[]},"dir":"ltr"},"config":{"plugins":["katex","-search","-lunr"],"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"pluginsConfig":{"katex":{},"highlight":{},"sharing":{"facebook":true,"twitter":true,"google":false,"weibo":false,"instapaper":false,"vk":false,"all":["facebook","google","twitter","weibo","instapaper"]},"fontsettings":{"theme":"white","family":"sans","size":2},"theme-default":{"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"showLevel":false}},"theme":"default","pdf":{"pageNumbers":true,"fontSize":12,"fontFamily":"Arial","paperSize":"a4","chapterMark":"pagebreak","pageBreaksBefore":"/","margin":{"right":62,"left":62,"top":56,"bottom":56}},"structure":{"langs":"LANGS.md","readme":"preface.md","glossary":"GLOSSARY.md","summary":"SUMMARY.md"},"variables":{},"title":"Go语言圣经","language":"zh-hans","gitbook":"3.x","description":"<The Go Programming Language>中文版"},"file":{"path":"ch6/ch6-04.md","mtime":"2020-08-13T07:15:34.335Z","type":"markdown"},"gitbook":{"version":"3.2.3","time":"2020-08-13T07:17:23.922Z"},"basePath":"..","book":{"language":""}});
        });
    </script>
</div>

        
    <script src="../gitbook/gitbook.js"></script>
    <script src="../gitbook/theme.js"></script>
    
        
        <script src="../gitbook/gitbook-plugin-sharing/buttons.js"></script>
        
    
        
        <script src="../gitbook/gitbook-plugin-fontsettings/fontsettings.js"></script>
        
    

    </body>
</html>

